Power operated lubricant compressor



April 16,1935. E w, DAWS f 1,997,860

POWER OPERATED LUBRICANT COMPRESSOR Filed May 18, 1932 2 Sheets-Sheet 1O J fw enzor':

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April 16, 1935.. E. w. DAVIS POWER OPERATED LUBRICANT COMPRESSOR FiledMay 18, 1932 2 Sheets-Sheet 2 Patented Apr. 16, 1935 UNITED STATESPATENT OFFICE.

POWER OPERATED LUBRICANT COMPRESSOR Application May 18, 1932, Serial No.612,121 19 Claims. (01. 221-411 My invention relates generally tolubricant compressors and more particularly to improvements in poweroperated lubricant compressors for supplying lubricant under highpressure.

It is an object of my invention to provide an improved lubricantcompressor which is of simple construction and which will be operativeto discharge heavy lubricants under high pressure.

A further object is to provide an improved lubricant compressor in whicha plunger is re ciprocated by a cam operating within the lubricantreservoir, the cam serving as means to aid in priming the high pressurecylinder.

A further object is to provide an improved form of outlet check valvefor high pressure pumps.

A further object is to provide a lubricant com j pressor with a smallnumber of parts, which has a long, useful life, which will be capable ofhandling various types of lubricants and which may be economicallymanufactured.

Other objects will appear from the iollowing description, referencebeing bad to the accompanying drawings, in which Figure 1 is a plan viewof the compressor with the lubricant receptacle and its connected partsremoved;

Figure 2 is a central vertical sectional view thereof, taken on the line22 ofFlgure l; Figure 3 is an end elevational view showing the operativeparts of the compressor in vertical section;

Figure 4 is an enlarged fragmentary sectional view showing the pumpplunger and cylinder and the pump operating cam; and

Figure 5 is a sectional view showing a modified form of pump outletcheck valve assembly.

The compressor compriizs a base casting i0 having a pair of supports l2bolted thereto, the supports l2 being provided with suitable means attheir extremities for the reception of swiveled casters M. A motor 56 isbolted to the base casting Hi and has its armature shaft'iS connected bya flexible coupling 20 with a cam shaft 22 suitably journaled inbearings 23, 28

formed in the base casting ill. -The base casting Hi has a sheet metallubricant supply container 28 welded or otherwise secured to an upwardlyextending flange 3b iormedintegrally with the base casting it). Thecontainer 28 is preferably funnel-shaped and has its upper end closed bya cover 32. A stirring rod 84, having a propeller 36 secured at itslower end, is mounted for rotation relative to the cover 32 and has ahandle 88 secured to its upper end.

A cam 40 is secured to the camshaft 22 by means or a set screw 42. Thecam is rotatable at one end of a channel 44 formed by ribs 46,

48 and 50. The cam engages a followerhead 52 secured to the end of aplunger 54. The 5 plunger 54 is reciprocable in a bore 56 formed in acylinder 58. The plunger 54 and cylinder 58 are preferably made ofextremely hard steel alloy, so that they will be capable of operation athigh speed for a long period without ap- 10 preciable wear.

The cylinder 58 has a pair of diametrically positioned inlet ports 60and has its outlet port at the end of the cylinder bore 56 normallyclosed by a. ball check valve 62 compressed against the end of thecylinder by a spring 64. The cylinder is secured in position in the basecasting In by a bushing 66 threaded in a bore 68, the bushing engaging aflange Ill formed on the cylinder 58 and pressing the latter against theend of the bore 68. A check valve fitting 12 is threaded in an enlargedbore 14 formed in the end of the cylinder 58 and serves as a seat forthe check valve spring 64. The fitting 12 is provided with a springpressed ball check valve 18, the spring of which is supported by a plugit. The fitting I2 is provided with a manually operable vent valveBil-and has a nipple 82 secured thereto. The nipple 82 has a conduit 84connected thereto, the other end of the conduit being connected to aT-flttlng 86. A discharge hose" 8B, which may be provided with the usualvalved control means for making a detachable connection with thelubricant receiving fittings attached to barrels to be lubricated isconnected 35 at one branch oi the T-fitting 86, the other branchcommunicating with a pressure-con- :trolled switch mechanism indicatedgenerally by the reference numeral 90. This pressure-controlled switchmay be of any well known con- 40 struction and is adapted to close theswitch to the motor whenever the pressure in the discharge line dropsbelow a predetermined minimum pressure, and to open the switch wheneverthe pressure exceeds a predetermined maximum value.

- A spring 92 is compressed between a shoulder 96 formed on the cylinder58 and the follower head 52, and normally holds the follower head incontact with the surface of the cam 40. 50

When the compressor is in operation, the motor rotates the cam 40 atrelatively high speed.. As indicated in Fig. 4, lubricant adheres to thesurface ofthe cam 40, which rotates in the direction indicated by thearrow, and the lubricant is thus caused-to circulate in a closed path,indicated by the arrows, past the inlet ports 60 of the cylinder 68.When relatively stiff, stringy lubricant is being used, this circulationcauses the lubricant to be worked up into a more plastic and fluidstate, so that it will more rapidly prime the high pressure cylinder.This circulation also causes a slight heating up of the lubricant. Thecirculation of the heated lubricant causes the gradual softening of thelubricant lying adjacent the path of circulation so that, as lubricantis ejected by the high pressure plunger, additional lubricant will berendered sufficiently fluid so as to be able rapidly to fiow into thehigh pressure cylinder to prime the-latter. The cam, of course, rapidlyreciprocates the high pressure plunger 54 and causes ejection of thelubricant past the check valves 62 and 16 under extremely high pressure.The grease gun continues in operation until the pressure is built up toa predetermined maximum value, when the pressure-controlled switch 90cuts out the supply of current to the motor. If and when lubricant isdischarged throughthe discharge hose 88, causing thepressure to dropbelow a predetermined minimum value, the automatic pressure-controlledswitch will close the circuit to the motor, whereupon the pump willimmediately commence operation. It will be noted, however, that themotor is not heavily loaded upon starting. If the lubricant fails tofeed to the high pressure cylinder, the propeller 36 may be manuallyrotated so as to force the lubricant into a position where it may beacted upon by the cam and the circulating lubricant. This will beunnecessary, however, under ordinary conditions, since the circulationof the softened and slightly heated lubricant by the cam will usuallycause the lubricant continuously to feed downwardly to the high pressurepump.

If desired, the check valve construction shown in Fig. 5 may be utilizedin lieu of .that previously described. As shown in this figure, thecylinder 58 has the end of its bore 56 closed by a ball check valve 96.A ball retainer 98 has a central spherical portion adapted to receivethe ball valve 96 and has a flange forming an abutment for a compressioncoil spring I00. An outlet fitting I02 is threaded in the enlarged bore14 of the cylinder 58, a suitable gasket I being interposed between thefitting and the cylinder to prevent leakage of lubricant. The outletfitting I02 is provided with a central bore I06, one end I06 of which isof reduceddiameter to form a guide for a check valve stem I I0, and theother end I I2 of which is of enlarged diameter and threaded to receivea bushing Ill. The bushing H4 forms a guide for the valve stem I I0 andis recessed to receive a packing I I6, the packing being held by apacking gland H8. The stem III] has an annular flange I20 forming anabutment for one end of a relatively strong compression coil spring I22,the other end of which is seated against the inner end of the bushing I.The stem H0 has a conical recess formed to receive the ball retainer 98and retain the latter in a central position relative to the bore 56 ofthe cylinder. The fitting I62 has one or more grooves I2| cut therein topermit flow of lubricant to the bore I06 of the fitting. The dischargeconduit I26 is secured in communication with the bore I06 by a suitablecoupling I28.

. The above described check valve construction spring I 22, since thelatter is substantially balanced by the differential pressures exertedupon the valve stem I I6. When, however, the pressure in the dischargeconduit is relatively low, substantialLv the full force of the springI22 is exerted upon the check valve stem and the check valve 96 istherefore forced very firmly against its seat. If, for example, aparticle of foreign matter becomes lodged between the check valve 96 andits seat, the pressure in'the discharge line will drop, due to leakagepast the check valve, thereby permitting the spring I22 to exert itsfull force upon the check valve, with the result that the foreign matterwill be crushed between the ball and its seat. The cross sectional areaof the portion of the valve stem II II which projects through thepacking gland H8, and which is exposed to atmospheric pressure, issufiiciently great that, when the compressor is operating at normalpressures, the lubricant pressure on the stem will be substantiallyequal to the force exerted by the spring I22. When operating under theseconditions, the pressure necessary to unseat the check valve 86 needtherefore be only sufiiciently greater than the pressure in thedischarge line to overcome the pressure of the spring I00. The use ofthis ball check valve construction makes it possible to operate thecompressor with a minimum consumption of electric power and yet providesan outlet check valve which will seat properly under all conditions ofoperation. It will be understood that when the pressure in the dischargeline is relatively high, the lubricant pressure on the ball check willitself exert a force upon the ball sumcient to force it tightly againstits seat.

tions in design and construction may be made 6 without departing fromthe spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a lubricant compressor, the combination of a lubricant supplychamber, a cam associated therewith rotatable within the lubricant insaid chamber, and a pump mechanism operated by said cam, said pumpmechanism'having a fixed inlet port adjacent said cam whereby lubricantwill beforced by said cam toward said inlet port.

2. Lubricating apparatus of the class described comprising a lubricantreceptacle, a motor driven cam rotatably mounted adjacent the bottom ofsaid receptacle, the bottom of said receptacle having a channel formedtherein beneath said cam and extending laterally thereof, and a highpressure lubricant pumping mechanism operated by said cam and-having afixed inlet portlocated adjacent said channel whereby lubricantcirculated through said channel by said cam will fiow past said inletport to aid in rapid priming of said pumping mechanism.

3. In a high pressure lubricant compressor for the discharge of stiffviscous lubricants, the combination of a lubricant reservoir, a motordriven follower head engageable with said cam, a spring for holding saidfollower head in contact with said cam, and walls partially surroundingsaid cam and said cylinder to form an open channel for conductinglubricant advanced by said cam totheinletportofsaidcylinder.

1,997,soo

4. In a lubricant compressor, the combination of a high pressurereciprocating plunger pump having an inlet port, a cam directlyengageable with the plunger of said pump for reciprocating the latter,and means including said cam for circulating and recirculating aquantity of lubricant greatly in excess of the volumetric capacitydriving said mechanism, a cam forming a driving,

connection between said power means and said pump, and means forming anopen channel for receiving lubricant adhering to said cam and conductingit to the inlet of said pump.

7. A high pressure grease compressor comprising a base casting having anopen channel formed therein, a driving element mounted in said castingand movable above said channel, means for supplying lubricant to saidchannel, a high pressure pump having an inlet port and operated by saiddriving element, said pumping means being located adjacent said channeland having its inlet port positioned to be supplied with lubricantcirculated through said channel by said driving element, whereby saidpumping mechanism will be rapidly and eifectively primed.

8. In a high pressure lubricant compressor, the combination of lubricantpumping means, a lubricant discharge conduit, a check valve having aseat between said pumping mechanism and said discharge conduit, and aspring pressed element having a portion thereof exposed to atmosphericpressure, said element engaging with said check valve to hold the latteragainst its seat.

9. In lubricating apparatus of the class described, the combination of apumping mechanism, an outlet check valve for said mechanism, a stemhaving one end thereof exposed to atmospheric pressure and the other endthereof engageable with said check valve, and a relatively strong springengageable with said stem to force the latter in a direction to engageand seat said check valve.

10. In lubricating apparatus of the class described, the combination ofpumping mechanism, an outlet check valve, a relatively light spring forholding said check valve in closed position, a relatively strong springoperable upon said check valve to force it to'its closed position, andmeans associated with said strong spring to decrease the pressureapplied thereby to said-check valve when the lubricant pressure on saidcheck valve tending to close the same is increased.

11. In a lubricant compressor for discharging lubricant under highpressure, the combination of a pumping mechanism having an outlet valveseat, a valve engageable with said seat, a relatively light spring forholding said valve on its said seat, a relatively strong spring forholding said valve on its seat, and lubricant pressure operated meansfor reducing the effective force of said relatively strong spring.

12. In apparatus of the class described the combination of a pumpingmechanism having a discharge port, a check valve for closing said port,and means for applying a variable force to said check valve in adirection to seat the same, said force being determined by the lubricantpressure on the discharge side of said check va ve.

13. In apparatus of the class described, the combination of a lubricantpumping mechanism, an outlet check valve therefor, means for applying arelatively constant resilient force to hold said check valve upon itsseat, and resilient means for applying an additional force on said valvein a direction to seat the same, said last named means exerting aneffective form responsive to the press re of the lubricant 0n thedischarge side of said check valve.

14. A high pressure lubricant compressor comprising a lubricantcontainer, 8. disc cam mounted for rotation within said lubricant,container,

power means for rotating said cam at relatively high speed, a plungerhaving its end engageable with said cam, a cylinder for said plunger,said cylinder having an inlet port therein, and means including an openchannel for conducting lubricant agitated by said cam to said inletport.

15. In combination, .a lubricant compressor having a unitary basecasting, a motor and a lubricant container mounted thereon, a cam shaftconnected to be rotated by said motor and journaled in bearings formedin said base cast ing, an eccentric cam secured to said shaft andpositioned at the bottom of said container in contact with lubricantcontained therein, a pumping mechanism positioned in the bottom of saidcon tainer and having a moving part operated by said cam, said pumphaving a stationary inlet port, and means formed integrally with saidbase casting for conducting'lubricant agitated upon rotation of said camtoward said inlet port.

16. In a high pressure lubricant compressor,

the combination of a lubricant container, a cam mounted for rotationnear the bottom of said reservoir, an open channel adjacent said cam toreceive lubricant agitated and fed by said cam, and a high pressure pumphaving a stationary inlet port positioned to receive lubricant from saidchannel.

17. In a high pressure lubricant compressor, the combination of alubricant container, a disc cam mounted for rotation near the bottom ofsaid container, and a high pressure pump driven by said cam and havingan inlet port positioned to receive lubricant displaced by said cam, andan open channel for conducting lubricant from said cam to said inletport.

18. In high pressure greasing apparatus, the combination of a reservoir,a high pressure pump supplied therefrom and having a fixed inlet port,and a stationary cam located within said reservoir to actuate said pumpand forming means to feed lubricant thereto.

19. In a high pressure grease feeding apparatus,v

means for rotating said cam at high speed.

ERNEST W. DAVIS.

GERTIFIATE 0F common y Patent No. 1,997,860. Q April .l6, 193s.

ERNEST w. DAVIS.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows:- Page 3,'second column,

line 60, claim 18, for "stationary" read disc; and that the said LettersPatent should be read with this correction therein that the same mayconform to the record of the case in'the Patent Office.

Signed and sealed this 25th day of June, A. D. 1935.

Bryan M; Battey (SeaI) a I Acting Commissioner of Patents.

